The Construction and Testing of YBCO Pancake Coils for a High Field Solenoid

Pancake coils are being fabricated using second generation (2G) High Temperature Superconductor (HTS) for a prototype 10 T solenoid. The length of conductor in each coil is 100 m and the inner diameter of the coil is 101 mm. The critical current of each coil was measured at 77 K in liquid nitrogen and down to ~20 K in helium gas. It has been observed that the effect of thermal shock during cool-down may cause coil performance to degrade irreversibly. The detailed results and the improvements to achieve 10 T will be discussed.